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Abstract:

Braid configurations in coaxial cables. In one example embodiment, a
coaxial cable includes a center conductor surrounded by a dielectric, a
first braid surrounding the dielectric, a second braid surrounding and
adjacent to the first braid, and a jacket surrounding the second braid.
The first braid is formed from a first material that is a conductive
material. The second braid is formed from a second material that is more
compressible and/or has a lower frictional coefficient than the first
material.

Claims:

1. A coaxial cable comprising: a center conductor surrounded by a
dielectric; a first braid surrounding the dielectric, the first braid
formed from a first material comprising a conductive material; a second
braid surrounding and adjacent to the first braid, the second braid
formed from a second material that is more compressible and/or has a
lower frictional coefficient than the first material; and a jacket
surrounding the second braid.

2. The coaxial cable as recited in claim 1, wherein the first material
comprises aluminum or copper.

3. The coaxial cable as recited in claim 1, wherein the second braid is
less tightly woven than the first braid.

4. The coaxial cable as recited in claim 1, wherein strands of the second
braid have a gauge that is smaller than a gauge of wires of the first
braid.

5. The coaxial cable as recited in claim 1, wherein the second material
comprises a polymer or an elastomer.

6. The coaxial cable as recited in claim 5, wherein the second material
comprises nylon.

7. The coaxial cable as recited in claim 1, wherein the second material
comprises glass.

8. The coaxial cable as recited in claim 1, wherein the second material
comprises carbon fiber or aramid fiber.

9. A coaxial cable comprising: a center conductor surrounded by a
dielectric; a first braid surrounding the dielectric, the first braid
formed from a first material; a second braid surrounding and adjacent to
the first braid, the second braid formed from a second material
comprising a conductive material, the first material being more
compressible and/or having a lower frictional coefficient than the second
material; and a jacket surrounding the second braid.

10. The coaxial cable as recited in claim 9, wherein the second material
comprises aluminum or copper.

11. The coaxial cable as recited in claim 9, wherein the first braid is
less tightly woven than the second braid.

12. The coaxial cable as recited in claim 9, wherein strands of the first
braid have a gauge that is smaller than a gauge of wires of the second
braid.

13. The coaxial cable as recited in claim 9, wherein the first material
comprises a polymer or an elastomer.

14. The coaxial cable as recited in claim 9, wherein the first material
comprises glass.

15. The coaxial cable as recited in claim 9, wherein the first material
comprises carbon fiber or aramid fiber.

16. A coaxial cable comprising: a center conductor surrounded by a
dielectric; one or more braids surrounding the dielectric, the one or
more braids comprising: a plurality of wires formed from a first
material; and a plurality of strands formed from a second material, the
first material comprising a conductive material and the second material
being more compressible and/or having a lower frictional coefficient than
the first material; and a jacket surrounding the braid.

17. The coaxial cable as recited in claim 16, wherein the first material
comprises aluminum or copper.

18. The coaxial cable as recited in claim 17, wherein the wires are
interwoven with the strands.

19. The coaxial cable as recited in claim 17, wherein the second material
comprises a polymer or an elastomer.

20. The coaxial cable as recited in claim 17, wherein the second material
comprises carbon fiber or aramid fiber.

21. A coaxial cable comprising: a center conductor surrounded by a
dielectric; a first conductive layer surrounding the dielectric; a braid
surrounding and adjacent to the first conductive layer, the braid formed
from a dielectric material; a second conductive layer surrounding and
adjacent the braid; and a jacket surrounding the braid.

22. The coaxial cable as recited in claim 21, wherein the first and
second conductive layers are braid layers.

23. The coaxial cable as recited in claim 21, wherein the first and
second conductive layers are tape layers.

24. The coaxial cable as recited in claim 21, wherein the one of the
conductive layers is a braid layer and the other conductive layer is a
tape layer.

Description:

BACKGROUND

[0001] Coaxial cable often includes an outer protective jacket that serves
to protect the internal components of the cable from external
contaminants and/or forces. For example, a typical coaxial cable includes
a center conductor surrounded by a dielectric, an outer conductor, and a
protective jacket. Some protective jackets are made from a relatively
rigid material in order to protect the internal components of the cable.
A cable with a rigid protective jacket can be especially useful when the
cable is installed outdoors, whether aerially or underground, due to the
extra protection provided by such a jacket.

[0002] Unfortunately, the rigidity of the protective jacket can give rise
to several problems. For example, a coaxial cable with a rigid protective
jacket can be very difficult to terminate with a typical cable connector.
A typical cable connector utilizes a post (or similar structure) that
must slide underneath and thereby expand the protective jacket to be
properly installed. A rigid protective jacket can require a high
insertion force to fully and properly insert the post underneath the
jacket. Further, because plastics become more rigid as they are exposed
to lower temperatures, the required amount of insertion force increases
with any drop in the ambient temperature of the cable. Consequently, cold
weather installation of a typical cable connector can be very difficult
or even impossible on a cable that includes a rigid protective jacket.

SUMMARY OF SOME EXAMPLE EMBODIMENTS

[0003] In general, example embodiments of the present invention relate to
braid configurations in coaxial cables. The example braid configurations
disclosed herein generally reduce the amount of insertion force required
to fully insert the post of a typical cable connector underneath the
jacket of a coaxial cable, even when the coaxial cable is exposed to low
temperature conditions.

[0004] In one example embodiment, a coaxial cable includes a center
conductor surrounded by a dielectric, a first braid surrounding the
dielectric, a second braid surrounding and adjacent to the first braid,
and a jacket surrounding the second braid. The first braid is formed from
a first material that is a conductive material. The second braid is
formed from a second material that is more compressible and/or has a
lower frictional coefficient than the first material.

[0005] In another example embodiment, a coaxial cable includes a center
conductor surrounded by a dielectric, a first braid surrounding the
dielectric, a second braid surrounding and adjacent to the first braid,
and a jacket surrounding the second braid. The first braid is formed from
a first material and the second braid is formed from a second material.
The second material is a conductive material. The first material is more
compressible and/or has a lower frictional coefficient than the second
material.

[0006] In yet another example embodiment, a coaxial cable includes a
center conductor surrounded by a dielectric, a braid surrounding the
dielectric, and a jacket surrounding the braid. The braid includes a
plurality of wires formed from a first material, and a plurality of
strands formed from a second material. The first material is a conductive
material and the second material is more compressible and/or has a lower
frictional coefficient than the first material.

[0007] In still another example embodiment, a coaxial cable includes a
center conductor surrounded by a dielectric, a first conductive layer
surrounding the dielectric, a braid surrounding and adjacent to the first
conductive layer, a second conductive layer surrounding and adjacent the
braid, and a jacket surrounding the braid. The braid is formed from a
dielectric material.

[0008] This Summary is provided to introduce a selection of concepts in a
simplified form that are further described below in the Detailed
Description. This Summary is not intended to identify key features or
essential characteristics of the claimed subject matter, nor is it
intended to be used as an aid in determining the scope of the claimed
subject matter. Moreover, it is to be understood that both the foregoing
general description and the following detailed description of the present
invention are exemplary and explanatory and are intended to provide
further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Aspects of example embodiments of the present invention will become
apparent from the following detailed description of example embodiments
given in conjunction with the accompanying drawings, in which:

[0010] FIG. 1A is a perspective view of an example coaxial cable that
terminates on one end with an example connector and that is prepared for
termination on the other end with another identical connector;

[0011] FIG. 1B is a perspective view of a portion of the example coaxial
cable of FIG. 1A with portions of each layer cut away;

[0012] FIG. 1C is a radial cross-sectional view of the example coaxial
cable of FIG. 1B;

[0013] FIG. 1D is an axial cross-sectional view of the example coaxial
cable and one of the example connectors of FIG. 1A;

[0014] FIG. 1E is a radial cross-sectional view of the example coaxial
cable and one of the example connectors of FIG. 1A;

[0015]FIG. 2A is a perspective view of a portion of a first alternative
coaxial cable with portions of each layer cut away;

[0016]FIG. 2B is a radial cross-sectional view of the first alternative
coaxial cable of FIG. 2A;

[0017]FIG. 3A is a perspective view of a portion of a second alternative
coaxial cable with portions of each layer cut away;

[0018]FIG. 3B is a radial cross-sectional view of the second alternative
coaxial cable of FIG. 3A; and

[0019]FIG. 3c is an enlarged view of a portion of the perspective view of
FIG. 3A.

DETAILED DESCRIPTION OF SOME EXAMPLE EMBODIMENTS

[0020] Example embodiments of the present invention relate to braid
configurations in coaxial cables. The example braid configurations
disclosed herein generally reduce the amount of insertion force required
to fully insert the post of a typical cable connector underneath the
jacket of a coaxial cable, even when the coaxial cable is exposed to low
temperature conditions. In the following detailed description of some
example embodiments, reference will now be made in detail to example
embodiments of the present invention which are illustrated in the
accompanying drawings. Wherever possible, the same reference numbers will
be used throughout the drawings to refer to the same or like parts. These
embodiments are described in sufficient detail to enable those skilled in
the art to practice the invention. Other embodiments may be utilized and
structural changes may be made without departing from the scope of the
present invention. Moreover, it is to be understood that the various
embodiments of the invention, although different, are not necessarily
mutually exclusive. For example, a particular feature, structure, or
characteristic described in one embodiment may be included within other
embodiments. The following detailed description is, therefore, not to be
taken in a limiting sense, and the scope of the present invention is
defined only by the appended claims, along with the full scope of
equivalents to which such claims are entitled.

I. First Example Coaxial Cable

[0021] With reference first to FIG. 1A, an example coaxial cable 100 is
disclosed. The example coaxial cable 100 can be any type of coaxial cable
including, but not limited to, 50 Ohm and 75 Ohm coaxial cable. As
disclosed in FIG. 1A, the example coaxial cable 100 is terminated on the
right side of FIG. 1A with an example connector 150, and is prepared for
termination on the left side of FIG. 1A with a second identical connector
150, as discussed in greater detail below. Although connectors 150 are
disclosed in FIG. 1A as F-type male connectors, it is understood that
cable 100 can also be terminated with other types of male and/or female
connectors (not shown).

[0022] With continuing reference to FIG. 1A, and with reference also to
FIGS. 1B and 1C, the coaxial cable 100 generally includes a center
conductor 102 surrounded by a dielectric 104, an optional conductive tape
106 surrounding the dielectric 104, a first braid 108 surrounding the
conductive tape 106, and a second braid 110 surrounding the first braid
108, and a jacket 112 surrounding the second braid 110. As used herein,
the phrase "surrounded by" refers to an inner layer generally being
encased by an outer layer. However, it is understood that an inner layer
may be "surrounded by" an outer layer without the inner layer being
immediately adjacent to the outer layer. The term "surrounded by" thus
allows for the possibility of intervening layers. Each of these
components of the example coaxial cable 100 will now be discussed in
turn.

[0023] The center conductor 102 is positioned at the core of the example
coaxial cable 100. The center conductor 102 can be configured to carry a
range of electrical current (amperes) and/or propagate an RF/electronic
digital signal. In some example embodiments, the center conductor 102 is
formed from solid copper, copper-clad aluminum (CCA), copper-clad steel
(CCS), or silver-coated copper-clad steel (SCCCS), although other
conductive materials are possible. For example, the center conductor 102
can be formed from any type of conductive metal or alloy. In addition,
the center conductor 102 can be solid, hollow, stranded, corrugated,
plated, or clad, for example.

[0024] The dielectric 104 surrounds the center conductor 102, and
generally serves to support and insulate the center conductor 102 and the
outer conductive tape 106. Although not shown in the figures, a bonding
agent, such as a polymer, can be employed to bond the dielectric 104 to
the center conductor 102. In some example embodiments, the dielectric 104
can be, but is not limited to, taped, solid, or foamed polymer or
fluoropolymer. For example, the dielectric 104 can be foamed polyethylene
(PE).

[0025] The optional tape 106 surrounds the dielectric 104 and generally
serves to minimize the ingress and egress of high frequency
electromagnetic radiation to/from the center conductor 102. For example,
in some applications, the tape 106 can shield against electromagnetic
radiation with a frequency greater than or equal to about 50 MHz. The
tape 106 is a laminate tape that can include, but is not limited to, the
following layers: aluminum/polymer, bonding agent/aluminum/polymer,
bonding agent/aluminum/polymer/aluminum, or aluminum/polymer/aluminum,
for example. It is understood, however, that the discussion herein of
tape is not limited to tape having any particular combinations of layers.

[0026] The first braid 108 surrounds the tape 106. The first braid 108 is
formed from a conductive material, such as aluminum or copper, and
generally serves to minimize the ingress and egress of low frequency
electromagnetic radiation to/from the center conductor 102. For example,
in some applications, the braid 108 can shield against electromagnetic
radiation with a frequency less than about 50 MHz. In addition, the braid
108 also serves to give structural support to, and thereby strengthen,
the coaxial cable 100. The braid 108 can be formed from inter-woven, fine
gauge aluminum or copper wires, such as 34 American wire gauge (AWG)
wires, for example. It is understood, however, that the discussion herein
of braid is not limited to braid formed from any particular type or size
of wire.

[0027] The second braid 110 surrounds the first braid 108. The second
braid 110 is formed from a material that is more compressible and/or has
a lower frictional coefficient than the material from which the first
braid 108 is formed. For example, where the first braid 108 is formed
from aluminum or copper, the second braid 110 may be formed from an
elastomer, a polymer, glass, carbon fiber, aramid fiber, or some
combination thereof. One suitable elastomer is silicone rubber. One
suitable polymer is nylon. In one example embodiment, the second braid
110 may be woven from a nylon monofilament.

[0028] The compressibility and/or relatively low frictional coefficient of
the material from which the second braid 110 is formed may be enhanced by
weaving the strands of the second braid 110 less tightly than the wires
of the first braid 108 are woven. For example, where the first braid 108
has 90% braid coverage, the second braid 110 may have 70% braid coverage.
Also, the compressibility and/or relatively low frictional coefficient of
the material from which the second braid 110 is formed may be enhanced by
forming the strands of the second braid 110 to have a gauge that is less
than the gauge of the wires of the first braid. Further, it is understood
that some strands of the second braid 110 may be formed from one
compressible and/or relatively low frictional coefficient material, while
other strands of the second braid 110 are formed from another
compressible and/or relatively low frictional coefficient material.

[0029] The jacket 112 surrounds the second braid 110, and generally serves
to protect the internal components of the coaxial cable 100 from external
contaminants, such as dust, moisture, and oils, for example. In a typical
embodiment, the jacket 112 also functions to limit the bending radius of
the cable to prevent kinking, and functions to protect the cable (and its
internal components) from being crushed or otherwise misshapen from an
external force. The example jacket 112 can be formed from a relatively
rigid material such as, but not limited to, polyethylene (PE),
high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear
low-density polyethylene (LLDPE), or some combination thereof. The actual
material used might be indicated by the particular
application/environment contemplated.

[0030] With reference now to FIG. 1D, and also with reference again to
FIG. 1A, aspects of termination of the example cable 100 with the example
connector 150 are disclosed. As disclosed on the left side of FIG. 1A,
prior to the termination of the example coaxial cable 100 with the
connector 150, a quarter-inch section 114 of the center conductor 102 and
a quarter-inch section 116 of the tape 106 are exposed. The quarter-inch
section 114 of the center conductor 102 is exposed by removing the jacket
112, the second braid 110, the first braid 108, the tape 106, and the
dielectric 104. The quarter-inch section 116 of the tape 106 is exposed
by removing the jacket 112 and then folding back a quarter-inch section
118 of the first and second braids 108 and 110 over the outside of the
jacket 112. Next, a cylindrical post 152 (or similar structure) of the
cable connector 150 can be inserted between the tape 106 and the first
braid 108. Finally, a wedge portion 154 of the connector 150 can be slid
down the coaxial cable 100 into the connector 150 in order to firmly
attach the connector 150 to the coaxial cable 100.

[0031] With continuing reference to FIG. 1D, and with reference now also
to FIG. 1E, additional aspects of termination of the example cable 100
with the example connector 150 are disclosed. As previously noted,
jackets made entirely from a rigid, substantially non-compressible
material such as PE tend to require an excessive amount of insertion
force to fully insert the post of a cable connector (or similar
component) underneath the jacket. However, as disclosed in FIG. 1E, as
the post 152 of the cable connector 150 is inserted between the tape 106
and the first braid 108, the post 152 displaces the strands of the second
braid 110 by causing the strands to compress and/or slip into unoccupied
space around the strands.

[0032] The displacement of the strands of the second braid 110 into the
unoccupied space around the strands is possible because the second braid
110 is not embedded in a solid layer but is instead woven, which
inherently results in region of unoccupied space around the strands
between the surrounding solid layers, namely, the tape 106 and the jacket
112. Where the strands of the second braid 110 are more compressible that
the wires of the first braid 108, the strands can deform into this
unoccupied space. Where the strands of the second braid 110 have a lower
frictional coefficient than the wires of the first braid 108, the strands
can slip past each other, or past the wires of the first braid 108, into
this unoccupied space. A lower frictional coefficient allows the strands
to move more freely relative to other strands with less surface adhesion.

[0033] The displacement of the strands of the second braid 110 into the
unoccupied space around the strands reduces the displacement of the
jacket 112 that is required to fully insert the post 152. Since the
strands of the second braid 110 are more easily displaced than the jacket
112, the relative decrease in the displacement of the jacket 112 reduces
the amount of insertion force required to fully insert the post 152 of
the connector 150 underneath the jacket 112.

[0034] Further, the second braid 110 is particularly advantageous in low
ambient temperatures. For example, although cold weather installation of
the cable connector 150 onto a standard rigid-jacketed cable can be
difficult or impossible due to the increased rigidity of the jacket in
cold temperatures, the cable connector 150 can be installed with relative
ease onto the example coaxial cable 100 in cold weather due to the
required insertion force being considerably reduced by virtue of the
compressible and/or relatively low frictional coefficient second braid
110. Therefore, the cable connector 150 can be installed on the example
coaxial cable 100 in cold weather where installation was previously
difficult or impossible with a standard rigid-jacketed cable. At the same
time, the relatively rigid jacket 112 provides the protection necessary
for the internal components of the coaxial cable 100.

[0035] In addition to the benefits of the second braid 110 discussed
above, the second braid 110 may also contribute to the tensile and
torsional strength and kink resistance of the coaxial cable 100. In
addition, to the extent that the inclusion of the second braid 110
reduces the thickness of the jacket 112 to maintain a consistent outer
diameter of the jacket 112, and to the extent that the second braid 110
is formed from a material that is lighter and/or less dense than the
material from which the jacket 112 is formed, the inclusion of the second
braid 110 can reduce the weight of the coaxial cable 100.

II. Alternative Coaxial Cables

[0036] It is understood that various alternative braid configurations are
contemplated to achieve the reduced amount of insertion force required to
fully insert a post of a connector underneath the jacket of a coaxial
cable. For example, with reference to FIGS. 2A and 2B, a first
alternative coaxial cable 100' includes first and second braids 108 and
110 but reverses their positions in the cable. In particular, the second
braid 110 surrounds the tape 106, and the first braid 108 surrounds the
second braid 110 in the first alternative coaxial cable 100'.

[0037] As noted above, the second braid 110 is formed from a material that
is more compressible and/or has a lower frictional coefficient than the
material from which the first braid 108 is formed. Accordingly, as a post
of a cable connector (such as the connector 150 disclosed in FIGS. 1D and
1E for example) is inserted between the tape 106 and the second braid 110
of the first alternative coaxial cable 100', the post displaces the
strands of the second braid 110 by causing the strands of the second
braid 110 to compress and/or slip into unoccupied space around the
strands, which reduces the amount of insertion force required to fully
insert the post of the connector underneath the jacket 112.

[0038] With reference to FIGS. 3A-3C, a second alternative coaxial cable
100'' includes a hybrid braid 114. As disclosed in FIGS. 3B and 3C, the
hybrid braid 114 includes a plurality of interwoven wires 114a and
strands 114b. The wires 114a are formed from the same materials discussed
above in connection with the first braid 108 and the strands 114b are
formed from the same materials discussed above in connection with the
second braid 110. For example, the wires 114a may be formed from aluminum
or copper, and the strands 114b may be formed from an elastomer such as
silicone rubber. As disclosed in FIG. 3c, two wires 114a are surrounded
by two strands 114b, which are in turn surrounded by two more wires 114a.
Therefore, in the embodiment disclosed in FIGS. 3A-3C, the hybrid braid
114 includes twice as many wires 114a as strands 114b. It is understood,
however, that other ratios of wires 114a and strands 114b are
contemplated. For example. The ratios of wires 114a to strands 114b may
be greater than or less than 2:1.

[0039] As noted above, the material from which the wires 114a are formed
is more compressible and/or has a lower frictional coefficient than the
material from which the strands 114b are formed. Accordingly, as a post
of a cable connector (such as the connector 150 disclosed in FIGS. 1D and
1E for example) is inserted between the tape 106 and the hybrid braid 114
of the second alternative coaxial cable 100'', the post displaces the
strands 114b of the braid 114 by causing the strands 114b of the braid
114 to compress and/or slip into unoccupied space around the strands
114b, which reduces the amount of insertion force required to fully
insert the post of the connector underneath the jacket 112.

[0040] Finally, although the example coaxial cables 100, 100', and 100''
disclosed herein include a single tape layer and one or two braid layers,
it is understood that the example braid configurations disclosed herein
may be employed in coaxial cables having: zero tape layers or two or more
tape layers; three or more braid layers; or a messenger wire; or having
some combination thereof. For example, a coaxial cable may include the
hybrid braid 114, as disclosed above in connection with the coaxial cable
100'', and also include one or more first braid layers 108 and/or one or
more second braid layers 110, as disclosed above in connection with the
coaxial cables 100 and 100'.

[0041] In addition, it is understood that the second braid layer 110 may
be employed as an insulator between two conductive layers. For example,
where the second braid layer 110 is formed from a dielectric material,
the second braid layer 110 may be positioned between two conductive braid
layers 108, between two conductive tape 106 layers, or between one
conductive braid layer 108 and one conductive tape layer 106 in order to
insulate the two conductive layers from one another. Therefore, the
second braid layer 110, when formed from a dielectric material, can
function to isolate two adjacent conductive layers.

[0042] The example embodiments disclosed herein may be embodied in other
specific forms. The example embodiments disclosed herein are to be
considered in all respects only as illustrative and not restrictive.